Abstract: Thiophene is continuously produced by reacting normal butane or a normal butene and hydrogen sulfide at elevated temperatures over a dehydrogenation catalyst, said reaction being conducted in the presence of sulfur vapor introduced in an amount to maintain the elevated reaction temperature and to overcome the heat loss caused by the endothermic reaction between the C.sub.4 hydrocarbon and hydrogen sulfide.The mole ratio of hydrogen sulfide to C.sub.4 hydrocarbon must be maintained within the range of 15 to 20 moles of hydrogen sulfide per mole of n-butane or n-butene. Conversions may vary from 60 to 20% per pass depending on catalyst activity. This requires that unreacted C.sub.4 hydrocarbon and hydrogen sulfide be recirculated. Carbon disulfide is a by-product of the reaction along with nominal amounts of other materials.